package org.smart4j.chapter2.helper;

import org.apache.commons.dbcp2.BasicDataSource;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.smart4j.chapter2.util.CollectionUtil;
import org.smart4j.chapter2.util.PropsUtil;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Properties;

/**
 * 数据库操作助手类
 * Created by chenchenghao on 2016/12/17.
 */
public final class DatabaseHelper {
    private static final Logger LOGGER = LoggerFactory.getLogger(DatabaseHelper.class);

    private  static  final  String DRIVER;
    private  static  final  String URL;
    private  static  final  String USERNAME;
    private  static  final  String PASSWORD;

    private static final QueryRunner QUERY_RUNNER ;
    private static  final ThreadLocal<Connection> CONNECTION_HOLDER ;
    private static final BasicDataSource DATA_SOURCE;

    static {

        CONNECTION_HOLDER =new ThreadLocal<Connection>();
        QUERY_RUNNER =new QueryRunner();

        Properties conf = PropsUtil.loadProps("config.properties");
        DRIVER = conf.getProperty("jdbc.driver");
        URL = conf.getProperty("jdbc.url");
        USERNAME = conf.getProperty("jdbc.username");
        PASSWORD = conf.getProperty("jdbc.password");

        DATA_SOURCE = new BasicDataSource();
        DATA_SOURCE.setDriverClassName(DRIVER);
        DATA_SOURCE.setUrl(URL);
        DATA_SOURCE.setUsername(USERNAME);
        DATA_SOURCE.setPassword(PASSWORD);

    }

    /**
     * 获得数据库连接
     * @return
     */
    public  static Connection getConnection(){
        Connection conn = CONNECTION_HOLDER.get();
        if(conn ==null){
        try{
            conn = DATA_SOURCE.getConnection();
        }catch (SQLException e){
            LOGGER.error("get connection failure",e);
            throw new RuntimeException(e);
        }finally {
            CONNECTION_HOLDER.set(conn);
        }
        }
        return conn;
    }

    /**
     * 关闭数据库连接
     */
    public static void closeConnection(){
        Connection conn = CONNECTION_HOLDER.get();
        if(conn!=null){
            try{
                conn.close();
            }catch (SQLException e){
                LOGGER.error("close connection failure",e);
                throw  new RuntimeException(e);
            }finally {
                CONNECTION_HOLDER.remove();
            }

        }
    }

    /**
     * 查询实体类List
     * @param entityClass
     * @param sql
     * @param params
     * @param <T>
     * @return
     */
    public static <T> List<T> queryEntityList(Class<T> entityClass,String sql,Object... params){
        List<T> entityList;

        try{
            Connection conn = getConnection();
            entityList = QUERY_RUNNER.query(conn,sql,new BeanListHandler<T>(entityClass),params);
        }catch (SQLException e){
            LOGGER.error("query entity failure",e);
            throw new RuntimeException(e);
        }finally {
            closeConnection();
        }
        return entityList;

    }

    /**
     * 查询实体类
     * @param entityClass
     * @param sql
     * @param params
     * @param <T>
     * @return
     */
    public static <T> T queryEntity(Class<T> entityClass,String sql,Object... params){
        T entity;

        try{
            Connection conn = getConnection();
            entity = QUERY_RUNNER.query(conn,sql,new BeanHandler<T>(entityClass),params);
        }catch (SQLException e){
            LOGGER.error("query entity failure",e);
            throw new RuntimeException(e);
        }finally {
            closeConnection();
        }
        return entity;

    }

    /**
     * 执行查询语句
     * @param sql
     * @param params
     * @return
     */
    public static  List<Map<String,Object>> executeQuery(String sql,Object... params){
        List<Map<String,Object>> result;
        try{
            Connection conn = getConnection();
            result = QUERY_RUNNER.query(conn,sql,new MapListHandler(),params);
        }catch (SQLException e){
            LOGGER.error("execute entity failure",e);
            throw new RuntimeException(e);
        }finally {
            closeConnection();
        }
        return result;
    }

    /**
     * 执行更新语句（包括update，insert，delete）
     * @param sql
     * @param params
     * @return
     */
    public static int executeUpdate(String sql,Object... params){
        int rows = 0;
        try{
           Connection conn = getConnection();
           rows = QUERY_RUNNER.update(conn,sql,params);
        }catch (SQLException e){
            LOGGER.error("execute update failure",e);
            throw  new RuntimeException(e);
        }finally {
            closeConnection();
        }
        return rows;
    }

    /**
     * 插入实体类
     * @param entityClass
     * @param fieldMap
     * @param <T>
     * @return
     */
    public static <T> boolean insertEntity(Class<T> entityClass,Map<String,Object> fieldMap){
        if(CollectionUtil.isEmpty(fieldMap)){
            LOGGER.error("can not insert entity: fieldMap is empty");
            return false;
        }

        String sql ="INSERT INTO " + getTableName(entityClass);
        StringBuilder columes = new StringBuilder("(");
        StringBuilder values = new StringBuilder("(");
        for(String fieldName : fieldMap.keySet()){
            columes.append(fieldName).append(", ");
            values.append("?,");
        }
        columes.replace(columes.lastIndexOf(", "),columes.length(),")");
        values.replace(values.lastIndexOf(", "),values.length(),")");
        sql += columes + "VALUES" + values;
        Object[] params = fieldMap.values().toArray();
        return executeUpdate(sql,params) == 1;

    }

    /**
     * 更新实体类
     * @param entityClass
     * @param id
     * @param fieldMap
     * @param <T>
     * @return
     */
    public static <T> boolean updateEntity(Class<T> entityClass,long id,Map<String,Object> fieldMap){
        if (CollectionUtil.isEmpty(fieldMap)) {
            LOGGER.error("can not update entity : fieldMap is empty");
            return false;
        }

        String sql = "UPDATE " + getTableName(entityClass) + " SET ";
        StringBuilder columns = new StringBuilder();
        for(String fieldName:fieldMap.keySet()){
            columns.append(fieldName).append("=?, ");
        }
        sql += columns.substring(0,columns.lastIndexOf(", "))+ " WHERE id=?";
        List<Object> paramList = new ArrayList();
        paramList.addAll(fieldMap.values());
        paramList.add(id);
        Object[] params = paramList.toArray();
        return executeUpdate(sql,params) == 1;

    }

    /**
     * 删除实体类
     * @param entityClass
     * @param id
     * @param <T>
     * @return
     */
    public static <T> boolean deleteEntity(Class<T> entityClass,long id){
        String sql ="DELETE FROM "+getTableName(entityClass) +" WHERE id =?";
        return executeUpdate(sql,id)==1;
    }

    public static String getTableName(Class<?> entityClass){
        return  entityClass.getSimpleName();
    }
}
